Self-priming centrifugal pump



March 23, 1954 E. M. SMITH SELF-PRIMING CENTRIFUGAL PUMP Filed Aug. 16, 195

INVENTOR. EDWA 222 M. s/w TH A 7 /VEYS Patented Mar. 23, 1954 1 1.672.812 SELF-"MING CENTIUFUGAL PUMP Gu -Bl! .lndultria, Inc.

nmu nolOhlo bio, agai nor to Bellville, Ohio.

Application Aai'mi i6, [850, Serb-l No. 179,767 x M (CL 103-413) priminl Pump. i. e.. one from inthepumpbodymaybeexpelledatmeinitlntion of pumping action.

Centrifugal plm'ipe which handle liquids intermittentlv while the impeller runs contlnuouzly become inoperative because of air trapped in the impeller chamber even though the liquid may be suppl ed irom'a'eouroe above the level oi the pump. This inoperative condition may be corrected either by venting the air through an additional vent tube which is not especially positive and is quite expensive. or by eausinz the pum to dlschme air again t the static head in the discharte pipe; 'Ihia latter method is preferable and various means for practieinz it hav been provided in lane pumps. but such means are not suitable (arose in small pumpa because oi the locket necessary space.

Tbo present invention solves the problem oi removinz air from the impeller chamber a centrifugal pump by providing a new meam and a new, method or mixing such air with liquid in the chamber and moving the mixture to the pump outlet where the air may escape from the pump.

The present invention will be better understoo d by those skilled in the art from the followintdescflptlon and the aooom ensirm drawinzain-whichz' Pix. 1 is a longitudinal, ccntrLL sectional view takenthrouzh e. pump embody l the present invention: r

Fix. 2'18 a cross-sectional view taken on line 1-7- 0! P 8. 1:

;P lz.'8 is a view similar to Fig. i. with parts ahowing a modified form oi the present invention: and

are central. lonzlwdinal. aeotioaalviewahkenuuouzhthemainbodieeoi pump housings embodyinz modification; o! the present invention.

The

body comprish that-troutwalllhmclinedat mallanaietorearwalllbuetothiaintiontheimpeller' lhaaazreater length. As ahown, the axial length 0! th chambcr decreases Iron: a maximum adjacent to the outlet 1 lo a minimum at said restriction opposite that outlet. Also due to this nclination oi iront wall I, the trout or intake edg of the impeller is spaced farther from the inner surface oi the front wall near outlet 1 than opposite the outlet and below outlet 1.

The inner surface 0! front wall I is provided with a. recees or depression II from a point adjacent the outer wall l to, or approximately to, the inlet 4. This recess or depression 10 is defined by a suriaoe Ii which is disposed longiiudinallv of the pump and extends into the wall I and a suflaee H which in inclined inwardly in the direction of rotation of the impeller from the outer end of surface II to the inner surface 0! wall I. Preferably, this re oess Or depression extenda radially but it may extend tamentially or spirally or otherwise.

The operation of the apparatus of Figs. 1 and 2 is substantially as follows: when the impeller chamber Ls partly tilled with liquid and the impeller L rotated it causes th liquid to now alone the surface 01 wall 1. A; the impeller move! the liquid downwardly toward the put of the chamber of shortest axial length. i. e the part opposite outlet 2, the radial depth 0! the liquid is inereaeed due to the oouvenenoe o! the euriwes of the front and rear end walla and 8. and u the impeller moves the liquid lmlflthla place of restriction to the upper and larzer part 0! the im eller chamber, the water increas s in axial length and decre ses in ereai'n a vacuum in the mien oineoeas ll. Rotation of the impeller causes the liquid to now acres! the recess repeatedly where it entnpe air. This i ir is carried .1008 with the liquid for, perhapr nveral revolution; and is gradually moved to the outer part oi the marine liquid man which anowofalrthronxh'the and recess. Thus. air is exhausted from the chamberandlnletwlth relultant primina oi the pump lnFiaJthemumiormixinltheairandthe liquid for the purpoae oiprtminlthepump eomprize: a modified form oi. reeenl iorminc apparatur. lnthileuetheinnermflmofihetront endwallloia umantil bparalleltothelnher rurlaoeottherearendwallkandthereoeuiia iaquitelikereoenllbutianotiormedinthe wallla. Thiareeeulloiaiormuibyaloncitudinal surfac Ila projecting inwardly from the i ner surface of wall 30 and extending radially from closely adjacent to the inner surface of cy limirical wall In to a place ndjuccnl to lhc inlet 40 From th inner surface or wall 30,:1 SUIIJCC Ila slopes inwardly to the Jlllrt; end of aurfnce I in the direction of rotation of the imp The operation of th pump of Hg. 3 is substnntially the some as that of 1 1g; land 2 except that it docs not include the vacuum cheating effect of the inclined front all I. When liq partly filling th impeller chamber 80 of Pig 3 is rotated and agltatcd therein by the impeller l. a partial vacuum is created when the liquid moves acniss recess and air drawn into that recess is thereupon mixed with the liquid Later lhL'. air escapes into outlet 20. Thus, the pump speedily primes Itself.

In Fig.4 is shown the main purl of an impeller housing like that shown in Pig. 3 with a depicssion ll therein formed by wall: If and I! like the correspondingly numbered parts of Fig. 1 but with front. wall 3!) being parallel to the rear will] (not shownl. The operation of the pump havlng a main housing part as shown in Fig. 4 is cut)- stantially the same as has been described above in connection with Fig 1 omitting, however, the action traceable to the convergence of the front end wall 1 toward the rear end wall 6.

In Fig. 5 is shown the main housing pnrt iii a centrifugal pump which Ls quite like the hou ing of Fig. 3 or 4 but the front end ill 3c is. pm Yidcd with an inner surface which is in the form of a spiral, Starting from the fltltt'l end of surface 21, this inner surface 20 gradually moves inwardly in the directio of rotntlon of the impeller and intersects with the inner end of surface 21. Thus, the impeller chambei decreases in axial length from the inner end of Klllitt II to the outer end thereof The action traceable to this inclination of the inner surface of front end wall is quit; like that described for the inclination of the front wall 3 of Fig. 1, i. 0., liquid being agitated and mixed with air and propelled downwardly 1n the chamber from an axially longer part of the chum her through the restricted part and then upward ly into an cnlarg d part will induce a flow of air into the chamber from the inlet opening and will then permit some of the air to escape through the outlet. The action of the recess formed by the intersection of surfaces 25 and 21 is substantiallv the same m that described above in connection with Fig. 3. i

It will be understood that any of the rvoessforming means of Figs 3, 4 and 5 may be used with either the spiral or lnclintJ inner surfaces of the main housing part and that if desir .d the inclined surfaces of the main housing "nu-u shown in Fig. 1 may be used without the [WE-111$! forming means of Figs. 1, .l and 4.

Having thus desczibed the present invention so that others skilled in the art may be able to understand and practice the same, I state that 4 what I deairc to secure by Letter! Patent la dc i'lnod in what is claimed.

What in claimai in:

l A centrifugal pump oompriailu a houcini :ncludlnq a cylindricltl aide wall havtng a peripheml outlet, :1 front end wall having n central inlet, a rear wall through which an impeller ahaft extends, the front wall being inclined to the rear wall said walla defining an tmpeller chamher having a portio of restricted axial length. and an impeller in aid chamber having a lesser clearance with the front wall in the region of said restricted length 2. A centrifugal pump comprising a housing including a cylindrical side wall having a periphcral outlet, a front end wall having a central inlet, a rear wall through which an impeller shaft ex ends, the front wall being inclined to the rear wall and including recess-totaling means, said walls defining an impeller chamber which decreases in axial length from the outlet aide to the opposite side, on impeller in said chamber having a greater clearance with the front wall adjacent said outlet and lesser clearance opposite said outlet, said recess-forming means extending radially on the inner side f said front wall 3v A self-priming centrifugal pump comprising a housing having a rear wall, a front wall provided with a central inlet, and a peripheral wall pro vided with an outlet and joining the outer peripheries of said rear wall and said front wall, said walls defining an impeller chamber, and means for mixing air and liquid in said chamber, said mixing means including an impeller rotat able in said chamber and coaxial with said inlet and substantially straight reoess-formmg means extending radially of the impeller axis along the inner side of said front wall adjacent to said impeller from said inlet substantially to said peripheral wall. saJd impeller serving, when rotated, to cooperate with said recessdorming means to mix air and liquid and to propel that mixture toward said outlet.

EDWARD M. SMITH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1.824.465 Carter c Sept. 22, 1931 2,100,365 Stratton 0 Nov. 30. 1937 2,217,211 Brady Oct. 8, 1940 2,291,138 Blom July 28, 1942 2,332,875 Stratum Oct. 26, 1943 2,444,100 Hill June 29,1948 2,461,865 Adams Feb. 15, 1949 2,463,251 Curtis Mar 1, 1949 2,581,828 Adams Jan 8, 1952 FOREIGN PATEN'IS Number Country Date 16,500 Denmark Sept. 26, 1912 274,809 Germany Jan. 16, 1914 

